Jae-min and Do-hyun

Hye-jin even though Jae-min hurts her as many times as he wants Hye-jin still tries to get along with him or even tries to have a conversation with him, even so Jae-min ignores her or says hurtful words when Hye-jin behaves well with him, with which Hye-jin feels bad even though Jae-min does not admit fault. When this happens Do-hyun is a great emotional support for Hye-jin since some time ago he promised to protect her from everything.

Every time Hye-jin tries to talk to Jae-min, he answers her badly or makes her feel bad, but with Do-hyun it's the opposite; he treats her well and makes her feel loved (Do-hyun also has feelings for Hye-jin that he hides).

Seo Hye-jin Intelligent, determined, very pretty, and dreams of becoming a great fashion designer. She has a past marked by misunderstandings with Jae-min. He was her first love, but the relationship ended in pain and resentment. Now, by fate, she works as an assistant and supervisor for both cousins, playing a key role in the competition for the inheritance. Although she claims her feelings for Jae-min are buried, her heart still holds memories she doesn't know if she wants to forget, nor does she know if she has feelings for Jae-min's cousin.

Seo Hye-jin comes from an average family but sometimes has money problems since she lives alone until she moves into the Han residence.

Han Seok-jin Tycoon and patriarch of the Han family. Owner of a multi-million-dollar business conglomerate, he wants to ensure he leaves his empire in capable hands, so he puts his grandchildren through a test in which they must work together... little knowing that the real battlefield will be Hye-jin's heart.

Han Do-hyun Jae-min's cousin and his complete opposite. Serious, reserved, and lethal in a fight, he has trained in martial arts since childhood. He arrived at the Han household as a teenager, having been estranged from the Han family by his mother. He is now deceased and has been recognized as the tycoon's grandson, although he would have preferred not to have any relationship with the Han family. He prefers to remain unnoticed and avoids conflict... except when it comes to protecting those he considers valuable. His relationship with Jae-min is tense and distant. Upon meeting Hye-jin, he develops a bond of trust with her, which arouses his cousin's jealousy.

Han Jae-min The childhood grandson of tycoon Han Seok-jin and the intended heir. Charismatic, not at all serious with women, and often giving them a gift with women that ends in failure, flirtatious, and with an excessive taste for luxury. A hardened and arrogant womanizer, he solves problems with money... although, if necessary, he isn't afraid to use his fists. Behind his Don Juan facade lies a man hiding a deep pain: Seo Hye-jin, the only woman he ever loved, whom he now treats with coldness and contempt, refusing to admit that she remains his weakest link.

The problem Jae-min had with Seo Hye-jin in the past was during a trip where Seo Hye-jin and Han Jae-min's family traveled to a travel house and on that trip Jae-min, Hye-jin and Hye-jin's brother went swimming in the pool where Hye-jin's brother drowned since he didn't know how to swim and Jae-min and Hye-jin couldn't do anything since they were still little. In conclusion, Han Jae-min feels guilty about what happened in the past since he couldn't do anything for Hye-jin's brother and that's why he now keeps his distance from Hye-jin.